Apparatus for applying metal coatings to valves



W. ISLER Get. 8, 1957 APPARATUS FOR APPLYING METAL COATINGS TO VALVESOriginal Filed April 17, 1954 'm'mvwx WILL/AM ASL/5R ATTORNEYS-2,808,804 APPARATUS FoR APPLYING METAL COATINGS T VALVES V WilliamIsler, Cleveland Heights, Ohio Original application April 17, 1954,Serial No. 425,995, now Patent No. 2,726,165, dated December 6, 1955.Divided and this application October 20, 1955, Serial No. 541,613

3 Claims. (Cl. 118-47) tion of such metal to the seat portions of poppetvalves,

for example, to rotate the valves at a uniform rate about a verticallydisposed axis, to preheat the area to be coated to a welding temperatureby means of gas flames, and to then progressively deposit the moltenprotective metal at a uniform rate upon successive portions of said areawhile continuing the rotation of the valve, said protective metal beingderived from the melting of welding rods. Such practive is disclosed byway of example, in Wagner Patent No. 2,301,763. a

The aforesaid'rnethod is disadvantageous in the following respects: (1)the necessity of rotating each'valve as the molten protective metal isapplied requires the use of a great deal of mechanism, including gears,chains, etc., which are likely to get out of order and requireconsiderable maintenance, (2) the application of protective metal by thegradual melting and depositing of molten drops upon successive portionsof the annular preheated zone (see line 55-68, first column, page 3 ofthe Wagner patent) is rather slow and difficult, particularly from thestandpoint of depositing the metal in uniform, predetermined amounts, itbeing stated in the Wagner patent that the total time required forpreheating and coating a valve head about two inches in diameter isapproximately ninety seconds, (3) the thickness and uniformity of thecoating is extremely difificult to control, so that a large portion ofthe aforesaid time is taken up by the necessity of spreading of themolten deposited metal by means of the, gas

torches subsequent to deposition of the metal (see line 69- UnitedStates Patent 2,808,804 Patented Oct. 8,1957

Fig. 3 is a transverse cross-sectional view, taken on:

the line 3-3 of Fig. 2,'and

Fig. 4 is a transverse the line 44 of Fig. 2.

which may be rotated by any suitable mechanism, such,t

for example, as that disclosed in the aforesaid Wagner patent. Theplatforml is provided at circumferentially' spaced points with circularrecesses 2, in eachof which is mounted an annular worksupporting member3 of heatrefractory material such as Alundum.

75, first column, page 3','and lines 7-12, second column;

page 3 of the Wagner patent), and (4) the fact that spree.

heating of the area to be coatedto a mere welding te'm perature is notsufficient to enable production robe speeded up toany extent.

The present invention has as its primary object appara- A tus forapplying protective metal coatings of the aforesaid character, wherebythe articles can be coated at much greater speed than has heretoforebeen possible, and in a much more eflicient manner, and whereby thethickness and uniformity of the coating are better controlled.

Other objects and advantages of the invention will be apparent duringthe course of the following description.

In the accompanying drawings, forming a part of this specification, andin which like numerals are employed to designate like parts throughoutthe same,

Fig. 1 is a plan view illustrating more or less diagrammatically onetype of apparatus which may be used for practising the invention;

Fig. 2 is a cross-sectional view, at approximately full size scale,taken on the line 22 of Fig. 1;

nate as the coating station, rotation of the platform 1 is stopped untilpleted.

When the valve has reached the station S and rotation of the platformlhas been stopped, an applicator head, generally designated by referencenumeral 8, is placed over the valve, as'shown in the drawings, and issupthe coating of the valve has been comported in the position shownuntil completion of the coating of the valve. I have not attempted toshow means for positioning and supporting'the head 8 during the coatingoperation, but it will be readily understood that any suitable mechanismmaybe provided for this purpose, and that the-positioning, supportingand removal of the head may be effected automatically, and insynchronism with the movements of theplatforrn '1. v

The applicator head 8 comprises a tubular torch or nozzle 9 providedwith a multiplicity of circumferentiallyspaced passageways 10 extendingthrough the wall thereof parallel with the axis of the nozzle. 7 aThreadedly secured to the upper end of the nozzle 9 is a hopper member11 having in its lower end an annular recess or groove 12, which'is inregistration with the upper ends of the passageways 10, and is'suppliedwith a combustible gas mixture through a pasageway 13 extending radiallythrough the member 11. 'The passageway 13 is supplied with gas by meansof a conduit 14 secured to the member ll.

The inner cylindrical surface 15 of the' nozzle 9 is Y flush with theinner cylindrical surface 16 of the hoppermember 11, and abovethe-surface 16, the hopper member 11 is provided with an outwardly andupwardly slop ing conical surface 17.

The hopper member 11 is provided with acover' or cap 18 having an airvent 19, andthe cap is providediwith an annular flange 20 which isinteriorly threaded forfl" the upper end of thehoppfer' threadedsecurement to member 11.

Secured, as by welding, -'to*the central portion of the lower surface ofthe cap '18 is a tubular member 21 which extends substantially to thelower end of the nozzle '9. The member 21 has a'portion22 of reducedexternal diameter the outer surface of which forms with the surfaces 15and 16 an annular passageway 23, through which powdered metal containedin the hopper ll may be dropped onto the zone 7 of the valve head.

It maybe noted that an annular shoulder '24 is pro-s vided at the upperend of the portion 22 of the member 21, and that the outer peripheraledge of this shoulder bears against the surface 17 of the hopper 11 whenthetcap 13 bears against theupper end 25 of the hopper, so as to stopofi flow of the powder into the passageway 22.

cross-sectional view, taken on When it is desired to feed powder, thecap 18 is unscrewed and the amount of powder fed is controlled by theextent to which the cap isaunscrewed. The member 21 thus constitutes ameans forcontrolling, on regulating the quantity of powder fed, as wellas a:passageway.-;for thepowder. e U I e The protective metals employedfor-coatingthe surs face, 7 of. the valve are preferably selectedfromhard facinghigh'temperature metals, of which those described in CapePatents 2,396,-552;.2;458,5,02"and2,48l,976, are

representative. These have melting points in the range 2400 F.2500 F.Another metal which mays be used.

forthis purpose is a Stellite composition-containing 6% cobalt, 30%chromium, and 4 tungsten, with the remainder iron, silicon andrn'anganese, and having a melting point of .about.240 FQ Thesemetals arepreferably in powder form',-and of a rnesh or-size such that they canflow freely into the pasagew'ayil Before the powder is fed.through thepassageway 22, and onto the seat portion 7 of the valve, the portion 7is preheated to a temperature atwhich actual melting of said surfaceoccurs. This preheating is accomplishedby igniting the gases-issuingfrom the lower end ofrthe passageways 10 andcausing-the. flame thus:produced to heat the surface 7 to the desired temperature. This actualmelting of said surface occurs at a temperature very-close to orapproximating the melting temperature of the valve material.

Since the passageways 10 are uniformly spaced about the valve seat, thesurface 7 is uniformly preheated, without the necessity of rotating thevalve. the need: for complicated mechanism usually provided for thispurpose.

After the surface 7 has been thus preheated, the flame is reduced inintensity, afterv which powdered metal, in

an amount sufiicient to provide the entire-hard facing for the valveseat, isdropped through the annular pas sageway 22 into the surface 7.Since the surface 7 has been heated to a high temperature, theparticlesof powdered metal will become'sintered to the surface 7 and toeach other, and in order to remelt the particles and-cause Thiseliminates 1 them to become bonded tothe surface 7, the flame is againincreased in intensity and continued in operationuntil a coating ofuniform character is formed. Since the powdered metalis uniformlydistributed about the valveseat, and is, uniformly heated-throughout thecircumference of the valve-seat; it. is unnecessary to rotate the valvein order to obtain such uniform distribution.

The method, as described, is also advantageous in that it takesconsiderably less time to coat the valves than isplatform may bestationary, and the applicator head:

moved into position over the valves successively. More-- over, aplurality of applicator heads maybe provided, so that coating ofallofthe valves on-the platform 'may beaccoinplished simultaneously.In-this latter case, a single hopper for all of the applicator heads maybe provided, as well as a single source of gas for all of the heads,thereby enabling production to be greatly speeded.

It may be noted that if desired, the valves may be individually rotatedabout their own axes during coating, since the apparatus and methoddescribed do not preclude such a possibility.

It is to be understood that various changes may be made in the apparatushereilrspecifically described without departing from the spirit of theinvention of thescope of the appended claims:

on said nozzle, a cover for said hopper member, means asociated withsaid hopper member and having atubular portion adapted to receive thestem of said valve, said} A tubular portion formingwith the'innersurfaceof said nozzle a passageway of annular transverse cross-section for theflowiof powdered metal from said'hopperm'ember onto said seatingsurface,and coacting means on said hopper member and last-named'means forcontrollingthe flow of powder from-said hopper member.

2. Apparatus, as defined in claiml, in which said means associated withsaid hopper is a tubular member secured to and depending from thecentralportion of said'covero 3; Apparatus for applying a protectivecoating to theseatingsurfaceof'a-poppet-type valve, said apparatuscomprising a cylindrical nozzle having inner and outer surfaces andhaving circumferentially-spaced passageways exte'nding through thenozzleparallelwith the axis of thenozzle, meansfor supplyinga'combustible gas-mixtureto 'said passageways, ahopper member mounted onsaid nozzle and provided with a conical inner'surfaee, a-

cover for said hopper membeiy a' tubular member securedto and dependingfrom the central portion of said cover and having an annular edgeadapted to coact'withsaid conical surface to shut off the flow of powderfromsaid hopper, and a tubular sleeve extendingfrom said tubular memberandadapted to receive the stem of the valve, said tubular. sleeveforming with the-inner surface of said nozzle'azpasageway of: annulartransverse crosssection for-thefiow. of powdered metal-from said hoppermember onto said heating surface.

References Cited in the'file ofthis patent UNITED STATES PATENTS2,049,575

I Sutton 1. Aug. 4, 1936 2,072,845; Benoit Mar. 9, 1937 2,108,998 SChoriFeb. 22, 1938 2,301,763- Wagner Nov; 10,1942.

2,317,173 Bleakley Apr. 20,-1 943 2,549,736 Wiese Apr. 17, ll 2,604,356Saudora July 22,. 1952 2,726,165

Isler Dec. 6, 19 55

